Skip to main content
ARS Home » Research » Publications at this Location » Publication #116458
Title: SITE OF ACTION OF A FLUORESCENT BRIGHTENER, CALCOFLUOR M2R, AS AN EFFICACY ENHANCER FOR THE LYMANTRIA DISPAR MULTINUCLEOCAPSID NUCLEOPOLYHEDROVIRUS (LDMNPV) IN THE GYPSY MOTH

Author
item DOUGHERTY, EDWARD - RETIRED
item NARANG, NEELAM
item GUTHRIE, KIM - FORMER ARS EMPLOYEE
item SHAPIRO, MARTIN
item BRAUN, SUSAN - FORMER ARS EMPLOYEE
item LYNN, DWIGHT

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Gypsy moth is a harmful pest of oaks and other deciduous trees in many parts of the United States and throughout the world. A gypsy moth virus, a nuclear polyhedrosis virus kills the larvae in nature. However, in the laboratory, the feeding of the stilbene fluorescent brighteners along with the virus increases the virulence of the virus about 2000 fold and decreases the time required to kill the gypsy moth larvae. The objective of this study is to determine the mode of action of these brighteners in the larval stomach in order to understand how to obtain optimal enhancement of the virus. We used different routes of infection and temporal administration to study the relationship between time of administration of virus and brightener, and virus enhancement. We also determined the viral and brightener's concentrations in the hemolymph after various hours of infection. We showed that brightener effected the virulence of the virus which was ingested, however brighteners did not go beyond the stomach. There was no change(both nucleic acid and proteins) in the progeny virus. This study will benefit scientists and companies involved in the production of biocontrol products to eradicate gypsy moth by providing insight into how and where viral activity is improved in the insect.

Technical Abstract: Fluorescent brighteners have been reported to increase the efficacy (lower the LC(50) of certain baculoviruses by as much as 2000 fold in laboratory tests. We designed a series of experiments to delineate the functions of fluorescent brightener 28(calcoflour M(2)R) and a multinucleocapsid nucleopolyhedrovirus of the gypsy moth, Lymantria dispar (LdMNPV) by using different routes of infection and temporal administration. We determined that both the occluded virus (OB) and the budded extra cellular virus (ECV) phenotypes had to be present simultaneously in the alimentary canal for optimum enhancement to significantly lower both LT(50) and LC(50). Several ingredients found in Grace's cell culture medium (which is similar to lepidopteran hemolymph) precipitate in the presence of fluorescent brightener. Levels of calcofluor M(2)R in the hemolymph were negligible. Occluded virus yields were reduced in virus infected L. dispar larvae in the presence of M(2)R. Progeny virus appeared normal as judged by protein and REN profiles and through insect bioassay, thus indicating that fluorescent brighteners probably do not permanently alter or mutate baculoviruses.